High sensitivity enhancement of multi-shaped silver-nanoparticle-decorated hydrophilic PVDF-based SERS substrates using solvating pretreatment

• Published in: Sensors and actuators. B, Chemical Chemical, 2021-11, Vol.347, p.130614, Article 130614
• Main Authors: Chin, Chia-ying, Chen, Cheng-cheung, Chen, Xin-an, Yen, Hui-ju, Hsien, Hsin-lun, Young, Jenn-jong, Chen, Yin-chuan
• Format: Article
• Language: English
• Subjects: Biomarkers; Dipicolinic acid; Ethanol; Hydrophilic PVDF-based SERS substrate; Hydrophilicity; Industrial applications; Low cost; Membranes; Multi-shaped Ag nanoparticles; Nanoparticles; Pretreatment; Rhodamine 6G; Sensitivity enhancement; Silver; Sodium chloride; Solvating pretreatment; Spores; Substrates; Suction; Vacuum filtration
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2021.130614

We report an extremely sensitive and ultra-low-cost PVDF-based SERS substrate using an easy fabrication process that can be conducted in a laboratory and scaled up for industrial applications. Hydrophilic PVDF membranes were sequentially dipped in ethanol and aqueous sodium chloride solution, following which multi-shaped Ag nanoparticles were deposited on the surface of the membranes by suction filtration. The simple solvating pretreatment led to an approximately 188-fold enhancement in the SERS signal intensity of R6G. Using the hydrophilic PVDF-based SERS substrate, subnanomolar sensitivity for R6G was achieved using 3 μL of sample volume on a 3×3 mm2 SERS substrate within 1 min detection time and without the need for concentration or drying processes. To demonstrate the feasibility of the developed SERS substrate as a sensor for bacterial spore detection, it was applied for the detection of the representative biomarker dipicolinic acid (DPA). The limits of detection of DPA and Bacillus spores were measured as 1 ppm and 5×103 spores/mL, respectively. The optimized configuration of low substrate area and wet micro-analyte volume makes the PVDF-based SERS substrate a simple and low-cost tool for the trace-level detection of small molecules in a rapid, sensitive, and high-throughput manner. [Display omitted] •An extremely sensitive and ultra-low-cost PVDF-based SERS substrate is reported.•The solvating pretreatment of PVDF led to 188-fold enhancement in the SERS signal.•A SERS spectrum was achieved using 3 μL of wet sample on a 9 mm2 SERS substrate.•LOD of B. subtilis spores was 5×103 spores/mL much lower than the infective dose.•An easy fabrication process can be done in a laboratory and scaled up for production.